The use of combustion chamber pressure sensors for detecting the pressure prevailing in the combustion chamber of an internal combustion engine is already known. Known combustion chamber pressure sensors usually have a longitudinal sensor body, which can be placed into a receiving opening on the cylinder head of the internal combustion engine. Such a combustion chamber pressure sensor is described in German Patent No. DE 103 12 174, for instance, which describes a combustion chamber pressure sensor whose housing forms a bore hole into which a transmission plunger made of ceramic material is inserted, whose one end is sitting on a measuring element and acting on it such that a measuring signal is generated which is proportional to the pressure to be detected, and whose other end is resting on a diaphragm sealing the bore.
German Patent No. DE 10 2005 025 062 describes a combustion chamber pressure sensor, in which the sensor element detecting the combustion chamber pressure is integrated into the housing of a sheathed-element glow plug.
The known combustion chamber pressure sensors use a conical sealing seat as a sealing device to seal the sensor body in the receiving bore on the cylinder head of the internal combustion engine. To this end, the steel jacket of the sensor body is provided with a conical sealing surface at its end on the side of the combustion chamber. Furthermore, the outer jacket has a screw thread with whose aid the sensor body is able to be screwed into the receiving bore, thereby pressing the conical sealing seat of the sensor body against a correspondingly shaped counter surface on the cylinder head, so that sealing is achieved. In order to obtain sufficient heat dissipation and vibration resistance, the conical sealing surface is placed as far forward as possible on the sensor body on the combustion chamber side, while the screw thread, due to the installation situation at the internal combustion engine, should be placed as far away as possible from the end of the sensor body on the combustion chamber side. As a consequence, the sensor body must absorb the torque applied during the screw-fitting and the resulting axial forces acting in the direction of the longitudinal extension virtually across its entire longitudinal extension.
Moreover, the sensor body of the known combustion chamber pressure sensors is virtually clamped between the conical sealing seat and the screw thread section, which is why deformations of the cylinder head caused by the combustion chamber pressure and also thermal expansions caused by the combustion process in the combustion chamber are transmitted to the steel jacket of the combustion chamber pressure sensor in their entirety. If the measuring element is not sufficiently decoupled from the sensor body, these deformations and thermal expansions are transmitted to the measuring element and may cause measuring errors in the measuring element. Some approaches therefore use a complicated construction in the interior of the sensor body in order to decouple the measuring element from the disadvantageous effects.